Boot Leak - help!

JasMin70

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Feb 20, 2026
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Fitted (new) original BMW Park Lane plates and an OEM "Z3" chrome badge after the boot respray - boot literally looked like someone had used it as a BBQ - so I do have an issue - the boot lid was taken off, painted and refitted but I have a leak (def a feature not a benefit) anyone else had boot leak issues and what did you do to fix it? cheers, ta, lotsu love, fanks!
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Eddie Zedder

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British Zeds
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Jun 10, 2015
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148
Location
Megawatt Valley, Notts.
Model of Z
Z3 2.0
The usual suspects will probably be at work here - 3rd brake light seal or the aerial grommet. Other possibilities are the light cluster seals, blocked roof drain wells (more likely to show up in the cabin) and as the lid has been off I would be checking it has been fitted back correctly and the seal is good.
 

Gatsoburner

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British Zeds
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Dec 16, 2025
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53
Location
North West of UK
Model of Z
3.0i
Depends where the water is sat.
My grommet caused NS rear well to fill with water.
3rd brake light caused water to pool at the back of the boot against thr bulk head under the roof.

New grommet sorted one, Resealed of the 3rd light bolts solved the other 🤞
 

Smudgemanuk

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British Zeds
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Dec 1, 2024
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Bicester, Oxford
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2.8l TU pre-facelift z3
Sorry if I am just stating the obvious but just in case
To see the rear well you need to remove the carpet in the NS corner of the boot.
 

RickyBobby

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Sheffield, South Yorkshire
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Z3 2.0 & VO18i
My money is on the 3rd brake light seal unless of course the aerial grommet is still the original and hasn't been renewed.

Easy to test which with a bottle of water and if it is the 3rd brake light there will likely be signs of corrosion on the bulb holder if you remove the plastic cover and have a look.
 

RickyBobby

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Z3 2.0 & VO18i
If it’s been resprayed did they replace the 3rd brake light seal ? Is it missing altogether ?
Definitely not the easiest thing to fit.

I remeber replacing a perished one on a previous Z3 with an OEM equivalent supplied by Sytner Sheffield - took me a few attempts to get it right before the leak was cured.
 

Gatsoburner

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British Zeds
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Dec 16, 2025
Points
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Location
North West of UK
Model of Z
3.0i
Tiny rubber washers were perished on mine. Ended up using a small amount of bathroom sealant on each bolt as a temp measure as I had nothing else. Intention was to buy from BMW but it's been dry since so reluctant to undo a fixed job !
 

JasMin70

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Joined
Feb 20, 2026
Points
28
Tiny rubber washers were perished on mine. Ended up using a small amount of bathroom sealant on each bolt as a temp measure as I had nothing else. Intention was to buy from BMW but it's been dry since so reluctant to undo a fixed job !
Smart, and if it works - jobs a good 'un :thumbsup:
 

JasMin70

Dedicated Member
Joined
Feb 20, 2026
Points
28
Definitely not the easiest thing to fit.

I remeber replacing a perished one on a previous Z3 with an OEM equivalent supplied by Sytner Sheffield - took me a few attempts to get it right before the leak was cured.
I fear I may be missing a seal .....
 

JasMin70

Dedicated Member
Joined
Feb 20, 2026
Points
28
Depends where the water is sat.
My grommet caused NS rear well to fill with water.
3rd brake light caused water to pool at the back of the boot against thr bulk head under the roof.

New grommet sorted one, Resealed of the 3rd light bolts solved the other 🤞
m'grommets are sound, thanks for askin :) - its for sure the third brake lite seal thing (or lack thereof) have ordered a new one
 

JasMin70

Dedicated Member
Joined
Feb 20, 2026
Points
28
The usual suspects will probably be at work here - 3rd brake light seal or the aerial grommet. Other possibilities are the light cluster seals, blocked roof drain wells (more likely to show up in the cabin) and as the lid has been off I would be checking it has been fitted back correctly and the seal is good.
3rd brake lite was the culprit - re-sealed all good now thx
 
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